Disclosed herein are phase change ink compositions, phase change ink vehicles, and methods for making same. More specifically, disclosed herein are phase change ink vehicles including fiber shaped nanowhiskers which can be used in direct and indirect printing processes. In one embodiment, the phase change inks are of the low energy type. In embodiments, phase change ink compositions are disclosed comprising (a) an ink vehicle; (b) a dispersing agent; (c) a colorant; and (d) organic fiber shaped nanowhiskers, inorganic fiber shaped nanowhiskers, or a combination of organic and inorganic fiber shaped nanowhiskers; wherein the organic fiber shaped nanowhiskers, the inorganic fiber shaped nanowhiskers, or a combination thereof, are encapsulated or functionalized to enhance compatibility with the ink vehicle; and wherein the colorant and the organic fiber shaped nanowhiskers, the inorganic fiber shaped nanowhiskers, or combination of organic and inorganic fiber shaped nanowhiskers are substantially resistant to aggregation and settling in the ink vehicle.
Another embodiment is directed to a method which comprises (a) incorporating into an ink jet printing apparatus the above-described phase change ink composition (b) melting the ink; (c) causing droplets of the melted ink to be ejected in an imagewise pattern onto an intermediate transfer member; and (d) transferring the ink in the imagewise pattern from the intermediate transfer member to a final recording substrate.
In general, phase change inks (sometimes referred to as “hot melt inks”) are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the recording substrate, either directly or via an intermediate heated transfer belt or drum, they quickly solidify to form a predetermined pattern of solidified ink drops. Phase change inks have also been used in other printing technologies, such as gravure printing, as disclosed in, for example, U.S. Pat. No. 5,496,879 and German Patent Publications DE 4205636AL and DE 4205713AL, the disclosures of each of which are totally incorporated herein by reference.
Phase change inks for color printing typically comprise a phase change organic phase change carrier composition which is combined with a phase change ink compatible colorant. In a specific embodiment, a series of colored phase change inks can be formed by combining organic phase change carrier compositions with compatible subtractive primary colorants. The subtractive primary colored phase change inks can comprise four component dyes, namely, cyan, magenta, yellow and black, although the inks are not limited to these four colors. These subtractive primary colored inks can be formed by using a single dye or a mixture of dyes. For example, magenta can be obtained by using a mixture of Solvent Red Dyes or a composite black can be obtained by mixing several dyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat. No. 5,372,852, the disclosures of each of which are totally incorporated herein by reference, teach that the subtractive primary colorants employed can comprise dyes from the classes of Color Index (commercially available from C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and Basic Dyes. The colorants can also include pigments, as disclosed in, for example, U.S. Pat. No. 5,221,335, the disclosure of which is totally incorporated herein by reference. U.S. Pat. No. 5,621,022, the disclosure of which is totally incorporated herein by reference, discloses the use of a specific class of polymeric dyes in phase change ink compositions.
Phase change inks have also been used for applications such as postal marking, industrial marking, and labeling.
Phase change inks are desirable for ink jet printers because they remain in a solid phase at room temperature during shipping, long term storage, and the like. In addition, the problems associated with nozzle clogging as a result of ink evaporation with liquid ink jet inks are largely eliminated, thereby improving the reliability of the ink jet printing. Further, in phase change ink jet printers wherein the ink droplets are applied directly onto the final recording substrate (for example, paper, transparency material, and the like), the droplets solidify immediately upon contact with the substrate, so that migration of ink along the printing medium is prevented and dot quality is improved.
Compositions suitable for use as phase change organic phase change carrier compositions are known and are described in U.S. Pat. No. 6,989,052, the disclosure of which is totally incorporated herein by reference.
U.S. patent application Ser. No. 11/423,777, filed Jun. 13, 2006, entitled “Organic Phase Change Carriers Containing Nanoparticles, Phase Change Inks Including Same, and Methods for Making Same,” Publication Number 20070283846, with the named inventors M. Breton, J. Belelie, P. Odell, R. Carlini, A. Goredema, B. Goodbrand and Nan-Xing Hu, the disclosure of which is totally incorporated herein by reference, discloses an organic phase change carrier and a method for forming same, and a phase change ink including same. The organic phase change carrier comprises a colloidal dispersion of nanoparticles exhibiting a substantially uniform distribution of said nanoparticles discretely distributed therewithin, at least one curable monomer; a phase change inducing component, and an initiator. The organic phase change carrier exhibits a substantially uniform distribution of the nanoparticles so that they are discretely distributed therewithin, and are substantially resistant to the aggregation of the nanoparticles distributed therewithin.
U.S. patent application Ser. No. 11/291,540, filed Nov. 30, 2005, entitled “Ink Carriers Containing Nanoparticles, Phase Change Inks Including Same and Methods for Making Same,” Publication Number 20070119340, with the named inventors Marcel P. Breton, Adela Goredema, Christine E. Bedford, Christopher A. Wagner, Sandra Gardner, Nan-Xing Hu, and Bruce Goodbrand, the disclosure of which is totally incorporated herein by reference, discloses an ink carrier and a method for forming same, and a phase change ink including same. The ink carrier comprises a colloidal dispersion of at least one of silica nanoparticles and metal oxide particles. The ink carrier can also include a low melting wax, and a gelling agent. The ink carrier exhibits a substantially uniform distribution of the nanoparticles so that they are discretely distributed therewithin, and are substantially resistant to the aggregation of the nanoparticles distributed therewithin.
Many phase change inks currently being used in solid ink jet piezoelectric printers employ low molecular weight polyethylene waxes in an attempt to achieve low jetting temperatures of less than about 120° C., print robustness, and low cost fabrication while maintaining jetting reliability.
While known compositions and processes are suitable for their intended purposes, a need remains for phase change inks having low jetting temperatures of less than about 120° C., print robustness, and low cost fabrication while maintaining jetting reliability. There further remains a need for phase change ink compositions having improved fracture resistance, improved transfuse latitude, and desirable fold characteristics. There further remains a need for improved optimization of the ejection process to enable jettability at higher viscosities. Also, there is a need for phase change inks having improved transfuse latitude and low stand-by energy. In addition, a need remains for phase change inks which exhibit robustness, that is resistance to scratch, crease and abrasion with substantially no smear. There is also a need for phase change inks that can exhibit at least some of the above advantages with reduced energy requirements while printing. In addition, a need remains for phase change inks that print successfully on paper and transparency stock. Furthermore, there is a need for phase change inks that generate prints with good performance in automatic document feeders.
The appropriate components and process aspects of the each of the foregoing may be selected for the present disclosure in embodiments thereof.